(1) Field of the Invention
This invention relates to a computer readable record medium on which a data communication load distribution control program used for performing data communication via a multiplexed transmission line is recorded and a data load distribution control method and, more particularly, to a computer readable record medium on which a data communication load distribution control program using trunking is recorded and a data load distribution control method.
(2) Description of the Related Art
One method for expanding a band which can be used for communication between a plurality of units is trunking. In trunking, units are connected via a plurality of transmission lines. Each unit treats network interface cards (NICs) connected to the plurality of transmission lines as one logical LAN port. This expands a band used for transmission between units.
FIG. 21 shows an example of the configuration of a conventional trunking system. A conventional trunking system comprises a computer 910, a switching hub 920, and computers 930, 940, 950, and 960 at the other end.
The computer 910 includes an application 911, a trunking mechanism section 912, and NICs 913 through 916. The application 911 is a processing function for communicating with the computers 930, 940, 950, and 960 at the other end and performing various kinds of data processing. The trunking mechanism section 912 treats the NICs 913 through 916 as one LAN port and communicates with the switching hub 920. The trunking mechanism section 912 has configuration information 912a where the media access control (MAC) addresses of the NICs 913 through 916, an internet protocol (IP) address shared by the NICs 913 through 916, and the like are set.
The NICs 913 through 916 are connected to the switching hub 920 via different transmission lines and perform data communication with the switching hub 920.
Four of eight LAN ports on the switching hub 920 are connected to the NICs 913 through 916, respectively, on the computer 910. The other four LAN ports are connected to the computers 930, 940, 950, and 960, respectively, at the other end.
In addition, the switching hub 920 includes a trunking correspondence section 921. The trunking correspondence section 921 has configuration information 921a including information, such as the IP address of a machine connected to each LAN port.
In the system the configuration of which has been described above, trunking is performed between the computer 910 and the switching hub 920. That is to say, the computer 910 uses the multiplexed NICs 913 through 916 for forming one logical NIC. The computer 910 then sends and receives data via the logical NIC.
The switching hub 920 sends data sent from the computer 910 to the computer 930, 940, 950, or 960 at the other end. In addition, the trunking correspondence section 921 included in the switching hub 920 assigns data sent from the computer 930, 940, 950, or 960 at the other end to one of the LAN ports connected to the computer 910 and sends the data to the computer 910 via the LAN port.
This expands a band which can be used for data communication between the computer 910 and the switching hub 920.
It is possible to control load distribution among a plurality of LAN ports without the switching hub 920 including the trunking correspondence section 921. For example, a host computer with a plurality of local area network (LAN) adapters informs a computer at the other end about the physical address of any LAN adapter. The computer at the other end specifies the physical address about which the computer was informed and sends data to the host computer. As a result, data sent from a plurality of computers at the other end can be received with the load distributed among the plurality of LAN adapters (see, for example, Japanese Unexamined Patent Publication No. 07-245619 (FIG. 1)).
With the conventional system, however, basically both the computer and the switching hub must have a trunking function to connect them. As a result, cases where trunking can be used are limited. Moreover, the number of NICs used in the computer, the number of ports used on the switching hub, distribution algorithms used in the computer and the switching hub are set as information. In this case, the number of the NICs used in the computer must be the same as that of the ports used on the switching hub and the same distribution algorithm must be used in the computer and the switching hub. In addition, dedicated MAC addresses for performing trunking must be defined. Accordingly, setting work is trouble and a user is apt to make a mistake.
Furthermore, if the number of the NICs used is increased or decreased, communication must be stopped temporarily to change the above information set in the switching hub. As a result, changing the set information lowers the operating ratio of the system.
If a trunking function is actualized by using only a switching hub without a trunking function, an NIC to be used can be determined by, for example, exchanging IP address information and MAC address information between computers. However, exchanging only address information puts a limit on a distribution algorithm. For example, if the number of computers at the other end is one, then only a specific NIC is used and load distribution cannot be performed.